Patent Document 1: Japanese Patent Laid-Open No. 2000-72250
A levitation transportation device has been known that an object being transported such as a semiconductor wafer in a molding/machining process is transported while being levitated by jetting airflow (See Patent Document 1, for example).
This type of levitation transportation device performs transportation while carrying out a molding/machining process at a predetermined molding/machining stage by combining a transfer unit and a control unit.
FIG. 6 shows a state where the semiconductor wafer as an object to be transported is being transported in a part of such transportation process, and a large number of jetting nozzles with jetting ports opened on the surface are arranged laterally and vertically on a back face of a transportation path 1 extending in a predetermined direction. Also, a guard 3 rises on the sides of the transportation path 1 in order to prevent removal of a semiconductor wafer 2 from the transportation path 1 when the semiconductor wafer 2 being transported is displaced from the center of the transportation path 1.
FIG. 7 shows an example of a jetting nozzle for levitating/transporting such semiconductor wafers. In FIG. 7, a jetting nozzle 4 is a columnar body held by a holding hole 5a of a holding plate 5 forming the transportation path 1, and a projecting portion 4a is formed at a part thereof for positioning not being capable of relative rotation by engaging a recess portion 5b formed in the holding hole 5a. Also, the jetting nozzle 4 is provided with a communication path 4b opened on the back face of the holding plate 5 and a nozzle 4c penetrating from the upper end of this communication path 4b to the upper end face in the inclined state.
By this, a pressure gas supplied to the back face of the holding plate 5 is jetted from the nozzle 4c through the communication path 4b. 
The inclination angle of the nozzle 4c, including a right angle, is determined by a transportation direction and the like of the semiconductor wafer 2.